A small waterfall or a series of small waterfalls; also, a process where one event causes a chain of similar events.
From French 'cascade', from Italian 'cascata', 'waterfall', from 'cascare', 'to fall', from Latin 'casus', 'a fall'. The physical falling water meaning later inspired the figurative 'chain reaction' sense.
When you hear about a 'cascade of failures' in a system, you’re really hearing waterfall language applied to disasters. The word asks you to picture problems tumbling down in steps, just like water over rocks.
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